Water Rocket Forum

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A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

I'm planning on making another attempt at the class B record this summer, and it's brought up another question. I don't mean to be a stickler for the rules, I just want to be sure I do it legitmately.

The current Class B record holding rocket (Millennium by Bruce Berggren) used a tomy timer on the outside of the rocket. I also used one on the booster of my JP-2 rocket. However, that does mean you have metal pieces (the spring and the shaft of the timer) on the outside of the rocket. According to a strict interpretation of the rules, that's not allowed, and I think some teams do take pride in avoiding even small pieces of metal like these. However, maybe one could say that these are enclosed by the plastic timer case, or maybe they are so small not to even to count as "parts".

My current booster on my new rocket also has a tomy timer on the outside to deploy the booster's chute. I could change it to an airspeed flap without too much hassle. So what do people think, is a tomy timer on the outside of the rocket okay?

SaskAlex wrote:I'm planning on making another attempt at the class B record this summer, and it's brought up another question. I don't mean to be a stickler for the rules, I just want to be sure I do it legitmately.

The current Class B record holding rocket (Millennium by Bruce Berggren) used a tomy timer on the outside of the rocket. I also used one on the booster of my JP-2 rocket. However, that does mean you have metal pieces (the spring and the shaft of the timer) on the outside of the rocket. According to a strict interpretation of the rules, that's not allowed, and I think some teams do take pride in avoiding even small pieces of metal like these. However, maybe one could say that these are enclosed by the plastic timer case, or maybe they are so small not to even to count as "parts".

My current booster on my new rocket also has a tomy timer on the outside to deploy the booster's chute. I could change it to an airspeed flap without too much hassle. So what do people think, is a tomy timer on the outside of the rocket okay?

Alex

Hi Alex,

No problem, that is the purpose of the Q & A forum. The metal bits inside the tomy timer would be allowed if enclosed inside a "bay". If the rocket should explode. That "bay" would separate from the rocket as a large piece rather than as small high speed dense shrapnel that small metal pieces such as steel washers, nuts bolts and screws which could be thrown at the speed of a gunshot.

From the safety rules.

The payload container has to be constructed from strong non-metallic materials to completely enclose any metallic parts carried inside (batteries, electronics, and mechanical components).
The payload section is to be attached above all pressurized parts of the rocket and cannot contain any exposed metal parts.
The payload section must be separate from any pressurized portions of the rocket.

What probably is needed is a rewording of the part stating that the payload section has to be attached above the pressurized portion since multiple stage rockets would have staging mechanisms and booster deployment systems in other places on the rocket. Maybe instead, we add another line covering staging/ booster recovery modules and that would do the trick.

Thank you for the input, your insight and experience building multiple stage rockets is appreciated.

Lisa Walker,Forum Administrator. The Water Rocket Achievement World Record Association